At its meeting in Helsinki in 2011, International Tunnelling Association Working Group 5, identified the need for guidance on the provision of refuge chambers in tunnels under construction. A refuge chamber is a place of relative safety in a shaft or tunnel where tunnellers can be accommodated with access to basic life support services until rescued or it is safe for them to exit the tunnel. Refuge chambers should be easily identifiable and readily accessible by tunnellers at risk and by the emergency services This document will be reviewed and revised as necessary in the light of practical experience with the provision of refuge chambers in tunnel under construction.